---
title: Versioning
type: docs
weight: 10
---

The Model Context Protocol uses string-based version identifiers following the format
`YYYY-MM-DD`, to indicate the last date backwards incompatible changes were made.

<Info>

The protocol version will _not_ be incremented when the
protocol is updated, as long as the changes maintain backwards compatibility. This allows
for incremental improvements while preserving interoperability.

</Info>

## Revisions

Revisions may be marked as:

- **Draft**: in-progress specifications, not yet ready for consumption.
- **Current**: the current protocol version, which is ready for use and may continue to
  receive backwards compatible changes.
- **Final**: past, complete specifications that will not be changed.

The **current** protocol version is [**2025-11-25**](/specification/2025-11-25/).

## Negotiation

Version negotiation happens during
[initialization](/specification/latest/basic/lifecycle#initialization). Clients and
servers **MAY** support multiple protocol versions simultaneously, but they **MUST**
agree on a single version to use for the session.

The protocol provides appropriate error handling if version negotiation fails, allowing
clients to gracefully terminate connections when they cannot find a version compatible
with the server.
